CN112198645A

CN112198645A - Zoom lens

Info

Publication number: CN112198645A
Application number: CN202011266934.1A
Authority: CN
Inventors: 葛杰; 金兑映; 宋亮
Original assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Current assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2021-01-08

Abstract

The invention discloses a zoom lens, which sequentially comprises a first lens group with positive focal power, a second lens group with positive focal power, a third lens group with negative focal power and a fourth lens group with positive focal power from an object side to an image side; upon zooming, the second lens group and the third lens group reciprocate along an optical axis; the object side surface of the first lens in the first lens group is a convex surface from the object side to the image side along the optical axis, and the first lens in the second lens group is set to be a positive power lens. The miniaturized structure can be applied to miniaturized mobile equipment such as mobile phones and the like, and continuous zooming can be realized.

Description

Zoom lens

Technical Field

The invention relates to the technical field of imaging, in particular to a zoom lens.

Background

With the continuous development of imaging CCD chips, the imaging chips are remarkably improved in volume and imaging quality. The miniaturized photographic lens at the present stage can realize high resolution and can also meet the light and thin size, so the miniaturized photographic lens is popular with consumers. The existing miniaturized camera lens mostly adopts single focus, is difficult to meet different requirements when a long shot and a short shot are shot at the same time, and causes inconvenience because the shooting of the long shot and the short shot can be met only by being equipped with a plurality of lenses. Therefore, a high performance miniaturized lens with a variable focal length has become a trend of high-order electronic products.

Disclosure of Invention

The present invention is to solve the above problems, and provides a lens with a smaller size and a variable focal length according to the requirement.

In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:

a zoom lens comprises a first lens group with positive focal power, a diaphragm, a second lens group with positive focal power, a third lens group with negative focal power, a fourth lens group with positive focal power, an optical filter and an image plane in sequence from an object side to an image side;

upon zooming, the second lens group and the third lens group reciprocate along an optical axis;

the object side surface of a first lens in the first lens group is a convex surface, and a first lens in the second lens group is set as a positive focal power lens; and satisfies the following conditional expressions:

TTL/IMGH<7

wherein, TTL is the total length of the zoom lens and unit millimeter; IMGH is the maximum half-image height of the zoom lens on an image plane, and the unit millimeter;

SD1/IMGH<3.3

wherein SD1 is the effective diameter of the first lens in the first lens group.

According to the preferred technical scheme, the first lens group at least comprises a positive focal power lens and a negative focal power lens; and a lens with positive and negative focal power;

the second lens group at least comprises a first positive focal power lens, a second positive focal power lens and a negative focal power lens;

the third lens group at least comprises a negative focal power lens;

the fourth lens group at least comprises a positive focal power lens.

Preferably, a diaphragm is disposed between the first lens group and the second lens group.

Preferably, the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are made of glass lenses or plastics.

According to the preferable technical scheme, the third lens group at least comprises one negative focal power lens, and the refractive index of the third lens group meets the following requirements:

1.6≤nd3≤1.78

where nd3 is the refractive index.

According to the preferable technical scheme, the zoom lens has the zoom multiples of:

1.4<Ft/Fw<2

wherein Ft is the telescopic focal length, Fw is the wide-angle focal length.

According to the preferable technical scheme, the zoom lens further satisfies the following relational expression:

-0.6<F3/F4<-0.3

wherein F3 is the focal length of the third lens group, and F4 is the focal length of the fourth lens group.

The invention has the advantages that:

in the present invention, a plurality of (for example, 8) lenses are used, and the optical lens has at least one gain effect of a small F-number, a small size, and a high-quality image by matching the focal power of each lens, the surface shape, the center thickness of each lens, the axial distance between each lens, and the like.

Drawings

Fig. 1 is a structural view schematically showing a wide-angle end of a zoom lens of embodiment 1;

fig. 2 is a structural view schematically showing a telephoto end of the zoom lens of embodiment 1;

fig. 3 is a wide-angle end chromatic aberration of magnification diagram schematically illustrating the zoom lens of embodiment 1;

fig. 4 is a wide-angle end field curvature diagram schematically illustrating the zoom lens of embodiment 1;

fig. 5 is a wide-angle end distortion diagram schematically illustrating the zoom lens of embodiment 1;

FIG. 6 is a diagram schematically showing chromatic aberration of telephoto magnification of the zoom lens according to embodiment 1;

FIG. 7 is a telephoto end curvature chart schematically showing the zoom lens of embodiment 1;

fig. 8 is a telephoto end distortion diagram schematically illustrating the zoom lens of embodiment 1;

fig. 9 is a structural view schematically showing a wide-angle end of the zoom lens of embodiment 2;

FIG. 10 is a structural view schematically showing the telephoto end of the zoom lens of embodiment 2;

fig. 11 is a wide-angle end chromatic aberration of magnification diagram schematically illustrating the zoom lens of embodiment 2;

fig. 12 is a wide-angle end field curvature diagram schematically illustrating the zoom lens of embodiment 2;

fig. 13 is a wide-angle end distortion diagram schematically illustrating the zoom lens of embodiment 2;

FIG. 14 is a diagram schematically showing chromatic aberration of telephoto magnification of the zoom lens according to embodiment 2;

FIG. 15 is a telephoto end curvature chart schematically showing the zoom lens of embodiment 2;

fig. 16 is a telephoto end distortion diagram schematically illustrating the zoom lens of embodiment 2.

Detailed Description

The invention is described in further detail below with reference to the accompanying figures 1-16 and examples.

A zoom lens comprises a first lens group with positive focal power, a diaphragm, a second lens group with positive focal power, a third lens group with negative focal power, a fourth lens group with positive focal power, an optical filter and an image plane in sequence from an object side to an image side; the first lens group G1 is provided with a diaphragm 4 on the image side, the second lens group is arranged on the image side of the diaphragm 4, the third lens group G3 is arranged on the image side of the second lens group G2, the fourth lens group G4 is arranged on the image side of the third lens group, and the optical filter 10 and the image surface 11 are arranged on the image side of the fourth lens group.

During zooming, the second lens group and the third lens group move back and forth along the optical axis in advance; the object side surface of a first lens in the first lens group is a convex surface, and a first lens in the second lens group is set as a positive focal power lens; and satisfies the following conditional expressions:

TTL/IMGH<7

wherein, TTL is the total length (unit millimeter) of the zoom lens; the IMGH is the maximum half image height (mm) of the variable focal length lens imaged on an image plane. The conditional expression can realize the optical total height of the lens as small as possible, thereby reducing the volume of the lens.

SD1/IMGH<3.3

Where SD1 is the effective diameter (in millimeters) of the first lens in the first lens group. The conditional expressions can realize the longitudinal height of the lens as small as possible, thereby reducing the volume of the lens.

The first lens group at least comprises a positive focal power lens 1 and a negative focal power lens 3; and a lens with positive and negative focal power; the second lens group at least comprises a first positive focal power lens 5, a second positive focal power lens 7 and a negative focal power lens 6; the third lens group at least comprises a negative focal power lens 8; the fourth lens group at least comprises a positive focal power lens 9. A stop is disposed between the first lens group and the second lens group. The lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are made of glass lenses or plastics. And more plastic lenses. The zoom lens is beneficial to expanding the field angle of the zoom lens at the wide-angle end, the aberration of a system can be effectively inhibited through the combination of the positive lens and the negative lens, the total length of the zoom lens is reduced, the total height of the lens can be effectively reduced, the system is miniaturized extremely, and the cost is lower.

In one embodiment, the third lens group comprises at least one negative power lens, and the refractive index of the third lens group satisfies:

1.6≤nd3≤1.78

the capability of the system for correcting chromatic aberration can be enhanced after the condition is met.

In one embodiment, the zoom factor satisfies:

1.4<Ft/Fw<2

wherein Ft is the telescopic focal length, Fw is the wide-angle focal length. When the zoom ratio is satisfied, the total length of the zoom lens is not too long.

In one embodiment, the following relationship is also satisfied: :

-0.6<F3/F4<-0.3

wherein F3 is the focal length of the third lens group, and F4 is the focal length of the fourth lens group. The refraction combination can be reasonably distributed after the condition is met, and miniaturization is easy to realize.

All the object side and image side surfaces of the variable focal length lens adopt aspheric surfaces, wherein the aspheric coefficients satisfy the following equation:

Z＝cy²/[1+{1－(1+k)c² y²}^+1/2]+A₄y⁴+A₆y⁶+A₈y⁸+A₁₀y¹⁰+A₁₂y¹²+A₁₄y¹⁴+A₁₆y¹⁶

wherein Z is an aspheric sagittal height, c is an aspheric paraxial curvature, y is a lens aperture, k is a conic coefficient, a4 is a 4-th aspheric coefficient, a6 is a 6-th aspheric coefficient, A8 is an 8-th aspheric coefficient, a10 is a 10-th aspheric coefficient, a12 is a 12-th aspheric coefficient, a14 is a 14-th aspheric coefficient, and a16 is a 16-th aspheric coefficient.

Example 1

The image sensor sequentially comprises from an object side to an image side: the lens comprises a first lens group, a diaphragm, a second lens group, a third lens group, a fourth lens group, an optical filter and an image surface; the second lens group and the third lens group move forward along the optical axis upon zooming from wide to tele. The first lens group has positive focal power, the second lens group has positive focal power, the third lens group has negative focal power, and the fourth lens group has positive focal power. The second lens of the second lens group and the first lens of the third lens group are made of glass, and the rest lenses are made of glass.

Fig. 1 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present application.

As shown in fig. 1, an optical lens according to an exemplary embodiment of the present application, in order from an object side to an image side along an optical axis, includes: the lens comprises a first lens group, a diaphragm, a second lens group, a third lens group, a fourth lens group, an optical filter and an image plane.

Table one (a) shows the surface type, radius of curvature, thickness, and material of each lens of the optical lens of example 1. Wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

The design parameters of the lens assembly of the present embodiment refer to the following table:

watch 1 (a)

Table one (b) shows surface aspherical coefficients of the respective lenses of the optical lens of example 1.

Watch 1 (b)

Flour mark

K

A4

A6

A8

A10

A12

A14

A16

1

-8.889E-01

-7.358E-05

8.583E-06

-8.645E-07

-2.987E-09

-4.516E-09

2

-2.912E+00

-2.698E-04

-1.753E-05

3.496E-07

-1.825E-08

-2.011E-09

3

5.167E+00

4.829E-05

1.384E-05

7.307E-07

3.243E-08

-2.364E-09

4

2.816E+01

-3.500E-05

-1.248E-05

3.611E-06

1.006E-07

-7.154E-09

5

-1.000E+02

-2.123E-04

9.597E-06

3.206E-06

7.234E-09

1.074E-08

6

3.914E+01

7.830E-04

5.154E-05

6.225E-07

-1.613E-07

1.024E-08

7

-1.056E+01

-1.539E-03

-2.954E-04

-1.798E-05

-8.343E-07

-2.790E-07

-3.377E-08

3.049E-09

8

-7.102E+01

8.920E-04

3.961E-05

-1.678E-05

-1.464E-07

1.638E-07

3.087E-08

3.221E-09

9

8.368E+01

-1.626E-04

4.028E-05

5.834E-06

1.516E-06

1.338E-07

2.403E-08

5.359E-09

10

-5.971E+00

1.215E-04

2.610E-05

2.413E-05

1.215E-06

1.980E-07

2.760E-08

-2.275E-09

11

2.811E+01

1.382E-03

1.278E-04

-1.488E-06

1.618E-06

1.335E-07

2.277E-09

-1.013E-09

12

1.150E+00

-1.023E-03

-5.444E-05

6.095E-06

-4.385E-07

-5.446E-08

-1.955E-09

-1.320E-10

13

1.641E+00

-4.337E-02

9.915E-03

-7.980E-04

1.355E-05

-6.860E-06

2.273E-06

9.107E-08

14

-8.139E+01

-2.473E-02

5.648E-03

-4.660E-04

-5.681E-05

1.042E-05

1.070E-06

-1.757E-07

15

4.044E-01

1.897E-03

-6.402E-05

-1.366E-05

6.395E-07

3.762E-08

5.393E-09

-1.304E-09

16

-9.765E+00

-4.284E-03

8.714E-04

-7.996E-05

1.440E-06

3.551E-08

3.465E-09

1.963E-09

The following table (c) lists the magnification-varying data of the zoom lens of the present invention:

watch 1 (c)

In this embodiment, the lens meets the requirements of the above claims, and the specific parameters are shown in the following table:

watch 1 (d)

Referring to fig. 1 and 2, which are 2D diagrams of the wide-angle end and the telephoto end of the optical system in embodiment 1, respectively, it can be seen that the close arrangement of the lenses of the lens can realize the smaller structural features of the lens.

Referring to fig. 3 and 6, on-axis color difference curves at the wide-angle end and the telephoto end, respectively, according to embodiment 1 are controlled within a small range.

Referring to fig. 4 and 7, astigmatism curves of the wide-angle end and the telephoto end, respectively, according to example 1, are controlled within ± 0.05mm, and the wide-angle end and the telephoto end have high resolving powers.

Referring to fig. 5 and 8, distortion curves at the wide angle end and the telephoto end, respectively, according to example 1 are controlled to within ± 2%, and distortions at the wide angle end and the telephoto end are well corrected.

Example 2

Fig. 9 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present application.

As shown in fig. 9, an optical lens according to an exemplary embodiment of the present application, in order from an object side to an image side along an optical axis, includes: the lens comprises a first lens group, a diaphragm, a second lens group, a third lens group, a fourth lens group, an optical filter and an image plane.

Table two (a) shows the surface type, radius of curvature, thickness, and material of each lens of the optical lens of example 1. Wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

The design parameters of the lens assembly of the present embodiment refer to the following table: watch two (a)

Watch two (b)

The following table two (c) lists the magnification-varying data of the zoom lens of the present invention:

watch two (c)

Center thickness	Wide angle end	Telescope end
			D6	4.695	1.002
D14	7.303	6.979
			D16	0.054	4.073

watch two (d)

Referring to fig. 9 and 10, which are 2D diagrams of the wide-angle end and the telephoto end of the optical system in embodiment 2, respectively, it can be seen that the close arrangement of the lenses of the lens can realize the smaller structural features of the lens.

Referring to fig. 11 and 14, on-axis color difference curves at the wide-angle end and the telephoto end, respectively, according to embodiment 2 are controlled within a small range.

Referring to fig. 12 and 15, astigmatism curves of the wide angle end and the telephoto end, respectively, according to example 2, are controlled within ± 0.05mm, and the wide angle end and the telephoto end have high resolving powers.

Referring to fig. 13 and 16, distortion curves at the wide angle end and the telephoto end, respectively, according to example 2, are controlled within ± 2%, and distortions at the wide angle end and the telephoto end are well corrected.

The embodiments of the present invention have been described in detail, but the description is only for the purpose of describing the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the invention are also within the scope of the present patent.

Claims

1. A zoom lens is characterized by comprising a first lens group with positive focal power, a diaphragm, a second lens group with positive focal power, a third lens group with negative focal power, a fourth lens group with positive focal power, an optical filter and an image plane in sequence from an object side to an image side;

TTL/IMGH<7

SD1/IMGH<3.3

2. The variable focal length lens of claim 1, wherein the first lens group comprises at least a positive power lens (1) and a negative power lens (3); and a positive and negative focal power lens (2);

the second lens group at least comprises a first positive focal power lens (5), a second positive focal power lens (7) and a negative focal power lens (6);

the third lens group at least comprises a negative focal power lens (8);

the fourth lens group at least comprises a positive focal power lens (9).

3. A variable focus lens as claimed in claim 1, wherein a stop is provided between the first lens group and the second lens group.

4. The variable focal length lens of claim 1, wherein the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are made of glass or plastic.

5. The variable focal length lens of claim 1, wherein the third lens group comprises at least one negative power lens, and the refractive index of the third lens group satisfies:

1.6≤nd3≤1.78

where nd3 is the refractive index.

6. The variable focus lens of claim 1, wherein the zoom factor satisfies:

1.4<Ft/Fw<2

wherein Ft is the telescopic focal length, Fw is the wide-angle focal length.

7. The variable focus lens of claim 1, further satisfying the following relationship:

-0.6<F3/F4<-0.3